1. Field of the Invention
The present invention relates to an piezoelectric control valve to be used for a fuel injector of an internal combustion engine. More particularly, it relates to a fuel injector for a diesel engine.
2. Description of the Related Art
In an attempt to increase the degree of freedom for the injection of a fuel, this fuel injection is often electronically controlled. However, when electronic control is used for injecting fuel in a diesel engine, a larger size control valve must be used to cope with the high fuel pressures involved, and thus the response characteristic becomes limited. Accordingly, in the conventional control valve, control of the time for starting the injection of a fuel is very difficult, and the degree of freedom of the control is very low. Accordingly, even pilot injection by controlling the injection rate is difficult, and a sufficient improvement cannot be attained in the reduction of engine noise or in the emission of exhaust gas.